On this site you will find pages with very accurate values of many much used technical units and physical constants, plus a periodic table of chemical elements and many other technically oriented articles. As much as possible the SI units system is followed. This material is subdivided into categories. If you don't know in which category something can be found, look it up in the large keywords index
A small taste of the contents:
* The exact value of the several British Thermal Units expressed in Joule.
* Conversions between energy equivalents like electronvolt, Joule, Hartree and cm-1
* The difference between international, ab and stat cgs units.
* An overview of water hardness units.
* Actual and historical values of the typographical point and pica.
* Several - but not too many - English units, including their mutual relationships.
* An overview of the most important units for radiation from radioactivity.
* How much radiation from radioactivity can men endure and what are the legal limits for exposure? How much radiation do we get from our environment?
* The IU weight units for vitamins.
* SAE numbers for engine oil and viscosity.
* Wine bottle sizes like Jeroboam and Nebuchadnezzar.
* Highlights from the electromagnetic spectrum, with many examples of radio bands, TV-bands, GSM, DECT, UMTS bands, radio astronomy, radar bands and more.
* Standards for the EM radiation from amongst others GSM telephones.
* How about the Hubble constant and the redshift?
* All powers of 2 up to 2128
* The latest values of many physical constants with derivations where appropriate.
* The periodic table of chemical elements with many physical properties.
* The names of the chemical elements in 48 languages.
* How cold or warm does it feel today? Equations for wind chill (windchill), heat index and humidex.
* Why is 10666
in the UK called undecicentillion, but in the US unvigintiducentillion? All about the names of big numbers.
* How much energy (joule) is released by an earthquake of magnitude 6 on the Richter scale?
* How are the Gaussian units related?
* From which countries are the internet URLs ending in .nl .at .to .nu .pro, et cetera? All official internet top level domain codes.
* How to convert blood glucose levels from milligrams per deciliter to millimols per liter?
* What's the difference between molarity, molality and osmolality?
* What's the difference between a metal, a semi-metal and a semiconductor?
* More than 1400 standard reduction potentials.
* How to use and encode quotes, hyphens and other typographic characters?
* How long ago was the Devonian? And the other geological era like Jurassic, Cretaceous, the ice ages?
* Suppose an asteroid will hit the earth. How large will the impact crater be?
* How many meters per second is Beaufort 9 and how much damage will be caused by a tornado with force F4 on the Fujita tornado scale?
* Extensive tables with American Wire Gauge, Birmingham Wire Gauge, Standard Wire Gauge, US Steel Wire Gauge, US Standard Gage, Manufacturers' Standard steel sheet Gage, Galvanized Sheet Gage, Standard Birmingham Gauge, Washburn & Moen music wire gauge, Stubs' Steel Gauge, Pin Wire Gauge, American drill diameters; and sizes of acupuncture needles, injection needles, catheters, suction- and oxygentubes, including color codes.
* Can the Ryznar index or Langelier index predict when carbonate will deposit from water?
* How on earth does one calculate the hyperbolic arctangent, haversine and other awkward gonio functions?
Well, let's stop here..., best you can go straight to the units! Click on Direct naar de eenheden.
So sorry, but most of these pages are only available in Dutch.
But wait, there is more! Starting 2014 you will find on this site our English pages on timezones, Unicode in browsers en working with colors.